In the evening, Dominique Arthur gave us a picture of a fish, hinting at some filming taking place at the London Aquarium. Ben and 3 supporting actors dressed as police officers were filming there, with at least some of it supposedly being shot in the aquarium tunnel. The crew also filmed some establishing shots from Westminster Bridge.
(I’m marking those last two points unconfirmed because there are no pics of what they filmed since they were indoors, but huge, huge thanks to @cupidford and @hotsmugstache for braving the elements today to bring us the scoop. We would definitely be missing out without you two superstars!)